1. Field of the Invention
The present invention relates to an endoscope to be inserted into a patient, in order to facilitate an observation inside the body cavity of the patient.
2. Description of the Background Art
In inserting a scope section of an endoscope into the body cavity of a patient, an operator is required to perform highly elaborated maneuvering of the endoscope in order to lead an end portion of the scope section, on which an imaging device is mounted, to a region of interest, while bending a middle portion of the scope section along the shape of the body cavity.
Also, in moving the scope section from one region of interest to another region of interest, the similar maneuvering of the endoscope is required.
In particular, the insertion of the scope section into various parts of the large intestine is known to require a difficult maneuvering of the endoscope. This is because the large intestine involve many portions which are curving in complicated manner, such as the sigmoid colon, the curving portion around the spleen, the transverse colon, and the curving portion around the liver.
For example, in FIG. 1, a procedure for inserting the scope section S into a portion between the sigmoid colon and descending color of a patient P is depicted in sequence. As can be seen from FIG. 1, the maneuvering required in such a case is quite complex, and can become even more sophisticated when an attempt is made to reduce the pain of the patient as much as possible.
In view of such a severe demand made on the operator, it is considered desirable to give as much of control of movements of the scope section as possible to the operator. In particular, in a course of elaborated operation of the endoscope such as that shown in FIG. 1, there are many occasions in which the middle portion of the scope section is desired to be stiff, while there are many other occasions in which the middle portion of the scope section is desired to be flexible.
However, in a conventional endoscope, a rigidity of the middle portion of the scope section is fixed and not adjustable, so that the maneuvering by the operator has been receiving a considerable limitation with regards the rigidity of the scope section.